U.S. patent application number 14/097966 was filed with the patent office on 2015-04-16 for common mode filter.
This patent application is currently assigned to Samsung Electro-Mechanics Co., Ltd.. The applicant listed for this patent is Samsung Electro-Mechanics Co., Ltd.. Invention is credited to Jin-Ho Hong, Young-Do Kweon, Chang-Bae Lee, Keun-Yong Lee, Sa-Yong Lee, Won-Chul Sim, Ju-Hwan Yang.
Application Number | 20150102886 14/097966 |
Document ID | / |
Family ID | 52809190 |
Filed Date | 2015-04-16 |
United States Patent
Application |
20150102886 |
Kind Code |
A1 |
Yang; Ju-Hwan ; et
al. |
April 16, 2015 |
COMMON MODE FILTER
Abstract
A common mode filter is disclosed. The common mode filter in
accordance with an embodiment of the present invention includes: a
magnetic substrate; a coil pattern formed on the magnetic
substrate; a dielectric layer formed on the magnetic substrate so
as to cover an upper part, a lower part and a side surface of the
coil pattern; and a first coupling agent interposed between the
magnetic substrate and the dielectric layer so as to prevent the
magnetic substrate and the dielectric layer from being
separated.
Inventors: |
Yang; Ju-Hwan; (Suwon,
KR) ; Sim; Won-Chul; (Suwon, KR) ; Lee;
Chang-Bae; (Suwon, KR) ; Hong; Jin-Ho; (Suwon,
KR) ; Lee; Keun-Yong; (Suwon, KR) ; Lee;
Sa-Yong; (Suwon, KR) ; Kweon; Young-Do;
(Suwon, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Samsung Electro-Mechanics Co., Ltd. |
Suwon |
|
KR |
|
|
Assignee: |
Samsung Electro-Mechanics Co.,
Ltd.
Suwon
KR
|
Family ID: |
52809190 |
Appl. No.: |
14/097966 |
Filed: |
December 5, 2013 |
Current U.S.
Class: |
336/196 |
Current CPC
Class: |
H01F 2017/0093 20130101;
H01F 17/0013 20130101 |
Class at
Publication: |
336/196 |
International
Class: |
H01F 27/30 20060101
H01F027/30 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 16, 2013 |
KR |
10-2013-0123493 |
Claims
1. A common mode filter comprising: a magnetic substrate; a coil
pattern formed on the magnetic substrate; a dielectric layer formed
on the magnetic substrate so as to cover an upper part, a lower
part and a side surface of the coil pattern; and a first coupling
agent having at least two functional groups so as to be bonded to
the magnetic substrate and the dielectric layer, respectively,
through the at least two functional groups that are different from
one another and interposed between the magnetic substrate and the
dielectric layer so as to prevent the magnetic substrate and the
dielectric layer from being separated.
2. The common mode filter of claim 1, further comprising a magnetic
layer formed on the dielectric layer.
3. The common mode filter of claim 1, further comprising an
external electrode connected to an end part of the coil pattern and
formed on the magnetic substrate in such a way that one surface
thereof is exposed to an outside.
4. The common mode filter of claim 1, wherein the first coupling
agent is made of a material including silane.
5. The common mode filter of claim 4, wherein the magnetic
substrate comprises ferrite and the dielectric layer comprises
epoxy.
6. The common mode filter of claim 1, further comprising a second
coupling agent interposed between the coil pattern and the
dielectric layer so as to prevent the coil pattern and the
dielectric layer from being separated.
7. The common mode filter of claim 1, wherein the magnetic
substrate comprises at least one of metal, polymer and ceramic.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of Korean Patent
Application No. 10-2013-0123493, filed with the Korean Intellectual
Property Office on Oct. 16, 2013, the disclosure of which is
incorporated herein by reference in its entirety.
BACKGROUND
[0002] 1. Technical Field
[0003] The present invention relates to a common mode filter.
[0004] 2. Background Art
[0005] High-speed digital interfaces, such as USB, require a part
that address noise. One of such parts that removes common mode
noise selectively is a common mode filter.
[0006] Common mode noise can occur when impedance fails to be
parallel in the wiring system. The common mode noise can occur more
often for higher frequency. Since the common mode noise can be also
transferred to, for example, the surface of the earth and bounced
back with a big loop, the common mode noise causes various kinds of
noise troubles in far-away electronic devices.
[0007] The common mode filter can allow a differential mode signal
to bypass while selectively removing the common mode noise. In the
common mode filter, magnetic flux is canceled out by the
differential mode signal, causing no inductance to occur and
allowing the differential mode signal to bypass. On the other hand,
magnetic flux is augmented by the common mode noise, increasing the
inductance and allowing the noise to be removed.
[0008] The related art of the present invention is disclosed in
Korea Patent Publication No. 2011-0129844 (COMMON MODE NOISE
FILTER; laid open on Dec. 6, 2011).
SUMMARY
[0009] The present invention provides a common mode filter having a
coupling agent interposed in between a magnetic substrate and a
dielectric layer.
[0010] The common mode filter in accordance with an embodiment of
the present invention can include: a magnetic substrate; a coil
pattern formed on the magnetic substrate; a dielectric layer formed
on the magnetic substrate so as to cover an upper part, a lower
part and a side surface of the coil pattern; and a first coupling
agent interposed between the magnetic substrate and the dielectric
layer so as to prevent the magnetic substrate and the dielectric
layer from being separated.
[0011] The common mode filter can also include a magnetic layer
formed on the dielectric layer.
[0012] The common mode filter can also include an external
electrode connected to an end part of the coil pattern and formed
on the magnetic substrate in such a way that one surface thereof is
exposed to an outside.
[0013] The first coupling agent can be made of a material including
silane.
[0014] The magnetic substrate can include ferrite, and the
dielectric layer can include epoxy.
[0015] The common mode filter can also include a second coupling
agent interposed between the coil pattern and the dielectric layer
so as to prevent the coil pattern and the dielectric layer from
being separated.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a cross-sectional view showing a common mode
filter in accordance with an embodiment of the present
invention.
[0017] FIG. 2 shows the structure of a silane coupling agent used
in the common mode filter in accordance with an embodiment of the
present invention.
DETAILED DESCRIPTION
[0018] Hereinafter, a certain embodiment of a common mode filter in
accordance with the present invention will be described in detail
with reference to the accompanying drawings. In describing the
present invention with reference to the accompanying drawings, any
identical or corresponding elements will be assigned with same
reference numerals, and no redundant description thereof will be
provided.
[0019] Terms such as "first" and "second" can be used in merely
distinguishing one element from other identical or corresponding
elements, but the above elements shall not be restricted to the
above terms.
[0020] When one element is described to be "coupled" to another
element, it does not refer to a physical, direct contact between
these elements only, but it shall also include the possibility of
yet another element being interposed between these elements and
each of these elements being in contact with said yet another
element.
[0021] FIG. 1 is a cross-sectional view showing a common mode
filter in accordance with an embodiment of the present invention.
FIG. 2 shows the structure of a silane coupling agent used in the
common mode filter in accordance with an embodiment of the present
invention.
[0022] Referring to FIG. 1, the common mode filter 100 in
accordance with an embodiment of the present invention can include
magnetic substrate 110, coil pattern 120, dielectric layer 130,
first coupling agent 140, magnetic layer 150, external electrode
160 and second coupling agent 170.
[0023] The magnetic substrate 110 is a board that is magnetic and
is placed at a lowermost location of the common mode filter. The
magnetic substrate 110 can include at least one of metal, polymer
and ceramic, which are magnetic materials.
[0024] The coil pattern 120 is a device that functions as an
inductor. The coil pattern 120 can be spirally formed to be
adjacent to one another but not to overlap with one another. The
spirally-formed coil pattern 120 can increase the length of the
pattern, thereby increasing the inductance.
[0025] The spiral-type coil pattern 120 can be formed in a
dual-layer structure. The first layer of coil pattern 120 has the
shape of winding from an outside to an inside, and the second layer
of coil pattern 120 has the shape of winding from an inside to an
outside. The first layer of coil pattern 120 and the second layer
of coil pattern 120 can be connected to each other at a center.
[0026] The coil pattern 120 can be constituted with a pair of
coils. Magnetic coherence occurs in between the pair of coils of
the coil pattern 120. In the case of common mode noise, the
inductance becomes augmented as the magnetic flux occurred by the
common mode noise is combined. As a result, the noise can be
removed.
[0027] The coil pattern 120 can be made of copper (Cu) or aluminum
(Al), which is highly conductive and workable. Moreover, the coil
pattern can be formed through photolithography and plating.
[0028] The dielectric layer 130 is a layer that surrounds the coil
pattern 120 and can insulate the magnetic substrate 110 and the
coil pattern 120. The dielectric layer 130 can be formed on the
magnetic substrate 110. Preferably used as a material for the
dielectric layer 130 can be polymer resin, which has a good
electrical insulation property and is highly workable, for example,
epoxy resin or polyimide resin.
[0029] The dielectric layer 130 can be partially formed before the
coil pattern 120 is formed, and then another portion of the
dielectric layer 130 can be successively formed after the coil
pattern 120 is formed so as to cover the coil pattern 120.
Accordingly, the dielectric layer 130 can cover all of an upper
part, a lower part and side surfaces of the coil pattern 120.
[0030] The first coupling agent 140 can be interposed between the
magnetic substrate 110 and the dielectric layer 130 so as to
prevent the magnetic substrate 110 and the dielectric layer 130
from being separated from each other. By interposing the first
coupling agent 140 between the magnetic substrate 110 and the
dielectric layer 130, a stronger chemical bond can be made between
the magnetic substrate 110 and the dielectric layer 130.
Accordingly, owing to the first coupling agent 140, it becomes
possible to prevent delamination between the magnetic substrate 110
and the dielectric layer 130.
[0031] The first coupling agent 140 can include silane coupling
agent. The structure of the silane coupling agent is illustrated in
FIG. 2. The silane coupling agent can have two or more functional
groups.
[0032] In FIG. 2, the first functional group (OR) is bonded with
metallic inorganic material included in the magnetic substrate 110.
In such a case, the first functional group is hydrolyzed and
chemically bonded (e.g., ionic bond) with a surface of the magnetic
substrate 110. The alkoxysilyl group (Si--OR) is hydrolyzed to
become a silanol group (Si--OH), which condensation-reacts with the
surface of the magnetic substrate 110. The second functional group
(X) is where the dielectric layer 130 is bonded (e.g., covalent
bond).
[0033] To realize the bonding by the silane coupling agent, the
silane coupling agent can be interposed between the magnetic
substrate 110 and the dielectric layer 130 and then heated to
200.degree. C.
[0034] In the case where the magnetic substrate 110 includes
ferrite and the dielectric layer 130 includes epoxy, an excellent
adhesion between the magnetic substrate 110 and the dielectric
layer 130 can be achieved by interposing the silane coupling agent
in between the magnetic substrate 110, which includes ferrite, and
the dielectric layer 130, which includes epoxy.
[0035] Referring to FIG. 1 again, the magnetic layer 150 is a layer
that is formed on the dielectric layer 130 and is magnetic. The
magnetic layer 150 forms a closed-magnetic circuit together with
the magnetic substrate 110. Magnetic coupling of the coil pattern
120 can be enhanced by the strong magnetic flux formed by the
magnetic layer 150 and the magnetic substrate 110.
[0036] The magnetic layer 150 can include magnetic powder and resin
material. The magnetic powder allows the magnetic layer 150 to be
magnetic, and the resin material allows the magnetic layer 150 to
have fluidity. In such a case, the magnetic powder can include
ferrite.
[0037] The external electrode 160 is connected with an end of the
coil pattern 120 and is formed on the magnetic substrate 110 so as
to have one surface thereof to be exposed to an outside. The
external electrode 160 can be formed on the dielectric layer 130.
The external electrode 160 is configured for inputting and
outputting a signal. The magnetic layer 150 can be formed by
avoiding the external electrode 160 so as to allow one surface of
the external electrode 160 to be exposed.
[0038] The common mode filter 100 in accordance with an embodiment
of the present invention can further include the second coupling
agent 170, which is interposed in between the coil pattern 120 and
the dielectric layer 130 so as to prevent the coil pattern 120 and
the dielectric layer 130 from being separated from each other. That
is, the second coupling agent 170 can be formed on a surface of the
coil pattern 120. In such a case, the second coupling agent 170 can
be made of components including silane.
[0039] By introducing the second coupling agent 170, coupling
between the coil pattern 120 and the dielectric layer 130 can
become stronger, thereby making the dielectric layer 130 insulate
the coil pattern 120 much better.
[0040] In the case where the coil pattern 120 is formed in a
dual-layer structure, the second coupling agent 170 can be coupled
to each layer of the coil pattern 120.
[0041] As described above, in accordance with an embodiment of the
present invention, coupling between the magnetic substrate 110 and
the dielectric layer 130 or between the coil pattern 120 and the
dielectric layer 130 can be improved. Particularly, as the coupling
is improved between the magnetic substrate 110 and the dielectric
layer 130, the delamination and crack of the magnetic substrate 110
and the dielectric layer 130 can be reduced. Delamination and crack
can allow moisture to be absorbed into the common mode filter 100
and adversely affect the reliability of the common mode filter 100.
Therefore, moisture resistance can be enhanced and the reliability
of the common mode filter can be improved by the above-described
coupling agent.
[0042] Although a certain embodiment of the present invention has
been described, it shall be appreciated that there can be a very
large number of permutations and modification of the present
invention by those who are ordinarily skilled in the art to which
the present invention pertains without departing from the technical
ideas and boundaries of the present invention, which shall be
defined by the claims appended below.
[0043] It shall be also appreciated that many other embodiments
other than the embodiment described above are included in the
claims of the present invention.
* * * * *